Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
FXUS64 KHGX 211151
Area Forecast Discussion
National Weather Service Houston/Galveston TX
651 AM CDT Fri Apr 21 2017
IFR to VFR conditions are in place at most terminals this morning
(save for Conroe, which is experiencing LIFR ceilings and fog),
with all sites expected to transition to VFR between 15-18Z.
Southerly winds around 5 knots inland this morning will increase
to 10-15 knots by mid-morning, with stronger gusts around 20
knots possible. A few showers may develop east of the terminals
within a cooridor of higher moisture, but overall coverage is
expected to be too low to include in the TAFs. Winds are expected
to fall below 10 knots 03-06Z as a cold front approaches the
terminals, with patchy fog and IFR/MVFR stratus possible again
tonight ahead of the front. The front is expected to reach College
Station around sunrise, reaching Houston mid to late morning, and
clearing the Upper Texas Coast during the afternoon. Cannot rule
out a few showers with the front, but weak convergence along the
front boundary and the presence of a low level capping inversion
will do a good job limiting overall development/intensity. North
winds will increase to around 15 knots behind the front inland,
closer to 20 (possibly 25 knots) along the coast.
.PREV DISCUSSION... /ISSUED 509 AM CDT Fri Apr 21 2017/
High pressure dominating the weather over SETX with upper
troughing over the Yucatan and Western Gulf with sharp upper
ridging spreading over SETX and a trough over WY/CO. Very active
weather across OK with severe weather along the front this
morning. Today the temperatures will continue to run well above
normal with strong capping and 850mb temperatures creeping up and
at 700mb rising 2-3C. Galveston scored another record yesterday
tying the record high temperature of 83 (previously set in 2006).
Don`t expect any records to be broken today but temperatures this
warm are normally seen around May 15th-19th. The unusual warmth
continues...for the official Houston Area the average temperature
January 1st-April 20th has been a whopping 66 degrees which beats
out the 1911 warmest of 65.3 degrees.
Upper trough over the Rockies will move east and southeast today
and Saturday which will push a front through the area Saturday. As
the front moves through NCTX tonight storms should develop and
spread southeastward probably reaching the northern portions of
SETX as early as 9 pm but greater chances for after midnight.
Scattered showers and a few thunderstorms will be possible over
the northern portions of SETX early Saturday morning ahead of the
cold front but a strong cap and lack of heating will be strong
inhibitors for storms. By sunrise the front should be edging into
the College Station to Crockett area. During the morning hours it
pushes on south at a steady clip and by noon should be over the
Houston Metro and off the coast by mid afternoon...prefrontal
troughing is a good bet to form. 850 flow goes westerly and is
very warm and anticipate that any showers and thunderstorms in the
early morning hours will probably decrease in coverage and shift
east quickly. Will carry 20 pops along the coast in the afternoon
and 30s in the Liberty/Chambers county where lingering strong low
level convergence should reside but those chances may be too high.
Moderate CAA taking place in the late morning through evening
hours will make for a much cooler afternoon/evening with breezy
conditions especially near the coast. High pressure rapidly builds
over the region drying us out with very pleasant weather on tap
High pressure drifts overhead Monday with temperatures dipping
into the 50s again Monday morning a few degrees cooler than Sunday
morning. Pressure falls over the Southern Plains Monday night will
commence a persistent southerly return flow that prevails through
Friday with unsettled weather Saturday and Sunday next week.
Temperatures will again soar back into the 80s Monday and may
flirt with 90 in the Houston Metro by Friday. Heat index readings
of 91-96 will be possible as early as Thursday and looks pretty
likely by Friday.
Light to occasionally moderate onshore flow and 2-4 feet seas will
persist through Saturday morning before a cold front pushes off the
Upper Texas coast Saturday afternoon. Small Craft Advisories are
probable behind the front for the bays and Gulf waters in response
to increasing offshore winds and elevated seas (3-6 feet nearshore,
5-8 feet offshore) through Sunday. Relaxing thermal and pressure
gradients as surface ridging builds into Texas should result in
improving conditions by Sunday night. Onshore flow resumes Tuesday
and strengthens through the end of next week as a storm system
develops over the High Plains.
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 87 65 73 50 73 / 10 50 20 0 0
Houston (IAH) 87 69 80 53 75 / 10 20 30 10 0
Galveston (GLS) 84 74 81 60 73 / 10 10 20 20 0